A large-scale power grid may be supplied from a number of different power source types. Typically the main power source is a type of thermal power generator, such as steam turbines based on coal, fossil fuel or nuclear fuel. Increasingly, however, wind power generators contribute to the overall power production in large-scale power grids. For operators of the power grids it is paramount to ensure stable and controllable power production of their power grids. Since wind turbine generators are relatively unstable power sources that fluctuate with wind conditions, wind turbine generators must be properly interfaced to the power grid to avoid carrying over instabilities into the grid since such instabilities can create disturbances that propagate trough the power grid system. To this end, the variability of wind creates a challenge to the integration of high levels of wind generated power into power grids.
In connection with controlling and monitoring wind generator turbines a Supervisory Control And Data Acquisition (SCADA) system is typically applied. A SCADA system may also be referred to as a Supervisory Command And Data Acquisition system. A SCADA system is on one hand configured to collect a large number of data from the wind turbine generators to which it is connected, and on the other hand configured to control the wind turbine generators to which it is connected by means of control routines feeding control parameters and settings to the wind turbine generators, so that a stable an controlled power supply can be ensured.
Solutions of the prior art relating to ensuring a stable and controllable power generation from a wind turbine generators include using meteorological modelling to predict changes in power production from wind turbine generators. In the published US patent application 2004/0207207 a power control interface is disclosed. A control system is disclosed that uses data derived from monitoring the power output form wind turbines generators of a wind farm and the power transmission line. Based on system-modelling algorithms the power output is predicted, and the power generation is stabilized by storing or releasing generated power in unstable periods. The system-modelling algorithms are based on meteorological predictions. Model-based solution, however, suffer from the fact that the combined system of external influences, e.g. meteorologically based, and internal influences, e.g. electrically based, is extremely complex and difficult, if not impossible, to model precisely.
The inventor of the present invention has appreciated that improved control of the power output from one or more wind turbine generators is of benefit, and has in consequence devised the present invention.